New genetic engineering techniques permit the expression in various organisms of genes coding for foreign proteins. One example of this, among many others, is the synthesis of human interferons by the yeast Saccharomyces cerevisiae (R. A. Hitzman et al., Science 219, 1983, 620).
A prerequisite of the expression of a gene in yeast is the location, upstream thereof, of a yeast promoter which is recognized by the yeast RNA polymerase II and causes the synthesis of the corresponding RNA messenger. Several such yeast promoters have already been described. In many cases, however, the expression levels obtained were low and impractical for industrial applications, especially when the promoters were used for the expression of foreign genes (T. Atkinson et al., Biochemical Soc. Trans. 12, 1984, 215).
There is a need for efficient promoters for genetic manipulation of yeasts in such a way that they can be used for practical purposes.